The onslaught is fueled not by the candidates but by outside groups that have delivered $9 million in mostly negative ads and contributed to an emerging and dramatic shift in politics:

The death of the local campaign.

Republican David Jolly and Democrat Alex Sink are supporting actors in an arms war that has turned the race into a simplistic, hard-hitting and often misleading referendum. Sink is cast as a liberal puppet in love with Obamacare; Jolly is characterized as a slick lobbyist bent on destroying Social Security and Medicare.

The candidates, like others in competitive races increasingly drawing outside money, have harnessed these themes at the expense of highlighting parochial issues and presenting themselves in a positive light. At once they are helped and hemmed in by independent groups, which have made the contest the most expensive special House election in history.

"It's incredibly frustrating," said Jolly, who has publicly criticized some of the attacks his allies made on Sink. "You would be hard pressed to find a voter in Pinellas County, who doesn't already know Alex or I, that's been able to make an informed decision simply on the TV commercials."

A swing seat after decades of Republican control, the 13th Congressional District has attracted outsized attention because it is the only game in the country at the moment, each side prepping for November's bigger war.

Still, the torrent of money, a significant amount from groups that keep the identities of donors a secret, has exceeded all expectations.

Nearly 200 political commercials have aired on TV each day. Ads dog people online and clog mailboxes, a daily dose of accusations and unflattering photos. When one outside group drops a new ad, it is followed by a call to attack from a group on the other side, an endlessly escalating game of mutual destruction.

"In just these last days — GOPers are spending $830,000 on negative, dishonest attack ads. We are down to the wire here. If we don't surge past our big deadline at midnight tonight . . . ," read an email Friday from the Democratic House Majority PAC.

Against it all, Sink and Jolly remain in a dead heat. Without the outside help, Jolly likely would have faded against Sink's superior fundraising. The winner gets to do it all again; the seat is back up for election in November.

"There's no question that candidates are less in control of their own destiny than ever before," said David Wasserman, who studies House races for the nonpartisan Cook Political Report.

Since 2004, the percentage of candidate spending in House races has fallen to 68 percent from 93 percent, according to Wasserman. In the Pinellas County race, candidate spending accounts for 30 percent.

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The transformation is driven by several factors. Because of gerrymandering and demographic shifts, only a handful of House seats hold the keys to party control, so those races have become increasingly intense.

A landmark 2010 U.S. Supreme Court ruling gave rise to super PACs and increased the presence of "social welfare" groups that can now accept unlimited donations from corporations, unions and individuals.

Meanwhile, Sink and Jolly face strict caps on donations ­­— $2,600 from an individual for the general election.

The effect is startling. In 2008, total outside spending topped out at about $300 million. After the high court's Citizens United ruling, it went to $450 million, more than a quarter of which came from groups that do not disclose their donors. In 2012, outside spending exceeded $1 billion.

"It raises questions about how this skews the democratic system," said Kathy Kiely, managing editor of the Sunlight Foundation, which tracks political spending. "There's a whole industry that's developed around outside money. They really are political war profiteers. They have no interest in advising a candidate to compromise or taking a higher tone because they never have to be held accountable."

The groups say they are exercising their right to participate in the political process.

"Floridians deserve to know that Alex Sink's dismal record for fewer jobs, more taxes and bigger government can't be trusted in Washington," said Emily Davis, spokeswoman for the conservative American Action Network, which has spent $500,000.

American Action Network, American Crossroads, the U.S. Chamber of Commerce and an array of smaller players, including the National Rifle Association, have helped Jolly match the firepower from Sink and outside groups in her corner.

"You appreciate the support of those who are in the fight with you," Jolly said. "But I am frustrated that I am not in the position to direct a message. We need a fix. The fix needs to be something that allows each candidate to be held accountable for everything voters see."

His campaign is sitting on a 60-second positive ad that it cannot afford to air. If he could coordinate with the groups, which he cannot by law, he would steer them toward that or a spot on the flood insurance crisis gripping Pinellas County or something on constituent service, a hallmark of the late Rep. Young.

Local flavor, however, is largely missing in the ads voters see.

Outside groups continue to launch salvos against the health care law and pummel Sink as a rubber stamp of President Barack Obama and House Democratic leader Nancy Pelosi.

"It's certainly a distraction," agreed Sink, adding she would work in Congress to tighten regulations on outside groups, particularly those that do not disclose the names of donors, including American Action Network and the U.S. Chamber of Commerce, which has spent more than $1 million attacking her.

Sink said she gets questions from voters about the health care law but "that issue might be fifth on the list." Of the torrent of ads, she says, "My hope is that the voters are paying attention."

But Sink has perpetuated the outside attacks on Jolly, accusing him in debates and a TV ad of trying to undermine Social Security and Medicare, distortions of the truth. The "dark money" flows on her side as well: A committee run by the Sierra Club contributed to a $350,000 TV ad running through Election Day that suggests Jolly is ignoring climate change.

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Tucked away on Sink's YouTube page is professionally shot video showing her talking with people at a café, walking with a man on the sidewalk and sitting with a young mother at a playground. There's no sound. It's "B-roll," in the parlance of video production, up for grabs for friendly outside groups that may need material for their ads.

Officially, campaigns cannot coordinate with outside groups but the video is one way they provide a hand without violating the law. Campaigns and outside groups also can communicate through the news media, publicizing the dates ads run and the amount of TV spending.

The Democratic Congressional Campaign Committee, which cannot coordinate with campaigns or other outside groups, maintains a website, dccc.org/races, that includes videos of Jolly and a 116-page opposition research book, mostly covering his work as a federal lobbyist, which opponents are free to use.

The National Republican Congressional Committee has its site, democratfacts.org, broken down by key districts across the country. The Sink section has video clips of Sink at debates, as well as high-resolution photographs for direct mail. One of the photos landed on a Republican Party of Florida mailer attacking Sink for her use of a state plane when she was Florida's chief financial officer.

Jolly said he decided not to go after Sink on the plane issue, knowing it was more nuanced, but that didn't stop the RPOF or the NRCC from airing a TV ad that misleadingly implied she used a state plane to travel to the Bahamas on vacation.

Jolly publicly criticized the ad, leading anonymous GOP officials to complain to Politico about the shortcomings of his first campaign.

The message: You would be dead without us.

"Outside groups certainly have a right to express their interest but it's not a healthy thing to have outside money eclipse the money controlling the message of the candidate," said Kenneth Gross, a former official with the Federal Election Commission.

"It drowns out the real issues that concern the people of Tampa Bay on a day-to-day basis," he added. "It's almost as if you are listening in on a presidential election."

Contact Alex Leary at leary@tampabay.com. Follow him on Twitter @learyreports.